Study on Abemaciclib and Abiraterone for Men with Prostate Cancer That Has Spread and Responds to Hormonal Treatment

Inclusion Criteria

• Diagnosed with prostate cancer that is mainly adenocarcinoma.
• Have high-risk prostate cancer that has spread to other parts of the body and responds to hormone therapy. High risk is defined as:
  • 4 or more bone metastases seen on a bone scan, and/or
  • At least 1 metastasis in organs like the liver or lungs seen on a CT or MRI scan.
• Must have started hormone therapy with medications that lower testosterone or had surgery to remove the testicles before joining the study. Up to 3 months of hormone therapy before joining is allowed, with or without certain anti-androgen medications.
• Must have good organ function.
• Must be in good overall health, with a performance status score of 0 or 1, meaning fully active or restricted in physically strenuous activity but ambulatory.

Exclusion Criteria

• Have previously been treated with abemaciclib or similar drugs that inhibit CDK4 & 6.
• Developed metastatic prostate cancer while having low testosterone levels.
• Have received any previous systemic treatment for metastatic prostate cancer, except for hormone therapy and certain anti-androgen medications.
• Have significant heart disease, such as a heart attack, blood clots, or severe chest pain in the past 6 months, or heart failure classified as Class II to IV.
• Have a history of fainting due to heart issues, abnormal heart rhythms, or sudden cardiac arrest. Stable atrial arrhythmia controlled with medication is allowed.
• Have uncontrolled high blood pressure.
• Have active or chronic liver disease or moderate to severe liver impairment.
• Have untreated cancer that has spread to the brain. Participants with treated brain metastases are eligible if stable for at least 8 weeks before joining the study and off steroids for at least 2 weeks before joining.